Automatic grinding and polishing machine



March 27, 1934. w v RQBINSQN 1,952,334

AUTOMATIC GRINDING AND POLISHING MACHINE Filed Aug. 30, 1930 4 Sheets-Sheet l INVENTOR Y W A 66 4 ATTORNEYS March 27, 1934. w. v. ROBINSON AUTOMATIC GRINDING AND POLISHING MACHINE Filed Aug. 30, 1930 4 Sheets-Sheet 2 w E N w W A INVENTOR WZZ ZZ 7 7 7/?0 March 27, 1934. w, v, ogmso 1,952,334

I AUTOMATIC GRINDING AND POLISHING MACHINE Filed Aug. 30, 1930 4 Sheets-Sheet 3 INVENTOR. 77722 274271 7 45270? BY 9W W A TTORNELS'.

March 27, 1934. w. v. ROBINSON AUTOMATIC GRINDING AND POLISHING MACHINE Filed Aug. 30', 1930 4 Sheets-Sheet 4 INVENTOR Patented Mar. 27, 1934 UNITED STATE AUTOMATIC GRINDING AND POLISHING MACHINE William V. Robinson, Owosso, Mich.

Application August 30,

3 Claims.

The invention relates to grinding and polishing machines adapted for the finishing of various articles such for instance as radiator shells, lamp casings, and other automobile parts. My im- 5 provement is particularly adapted for the finishing of parts formed of noncorrodible ferrous alloys, commonly known as stainless steel, and it is one of the objects of the invention to automatically perform all of the operations for rough grinding and polishing work during the progressive advancement of the same, requiring attention only in placing the work upon and removal from the carrier.

It is a further object of the invention to obtain a construction in which the grinding units which constitute the progressive series are independently controlled, permitting the operator at any time to remove and replace a particular grinder wheel without stopping the operation of the series. Still further it is an object to obtain a construction in which the working parts are protected from the dust of grinding. With these and other objects in view the invention consists in the construction as hereinafter set forth.

In the drawings:

Figure l is a sectional end elevation of the machine;

Figure 2 is a side elevation thereof;

Figure 3 is a plan view;

Figure 4 is an elevation of the mechanism for converting continuous rotary motion to oscillatory motion;

Figure 5 is an enlarged view of a portion of the mechanism shown in Figure 1; and

Figure 6 is an enlarged elevation of a portion of the mechanism shown in Figure 2.

While my improved machine is adapted to operate on various automobile parts and other articles I will specifically describe a construction adapted for the finishing of automobile radiator shells. These shells are formed from pressed sheet metal, being provided with a front face apertured for the exposure of the radiator core and a continuous flange forming the top, sides and 5 bottom. The surfaces to be polished are the sides and top of the flange and also the front face, but I have illustrated only the operation of grinding and polishing the front face.

In detail, A are vertical arched standards arranged in series and connected to each other to form a supporting structure for as many separate grinding and polishing wheels as may be required. Between these standards A are arranged vertical swinging frames 3 which carry at their lower ends horizontally extending grind- 1930, Serial No. 479,038

er frames C pivotally supported upon a shaft D. At their upper ends the frames B are pivotally connected at E to links F which in turn are pivotally connected at G to the upper ends of the standards A. Intermediate the upper and lower ends of the frames B are supporting rollers H which are adapted to be driven on tracks I, thereby supporting the weight of both frames B and C and the mechanism carried thereby. The tracks I are supported from the standards A to extend forward therefrom the beams J are also secured tosaid standards to project forward therefrom.

Each of the horizontaleframes C has a portion projecting forward from the shaft or pivot D and carrying at its forward end one or more grinder or polishing wheels K. The frame also has a portion extending rearward from the pivot D on which is mounted an electric motor L connected by the belt M with pulleys respectively on the arbor of the grinder K and on the motor shaft. The forward and rear portions of the frame are so adjusted in length with respect to the weight carried that the grinder wheel will be actuated by gravity with just suflicient force to conform to the surface of the work and to satisfactorily perform the grinding or polishing operations. This force may be adjusted by the shifting of a counter-weight C upon the rear portion of the frame C and by means of an operating rod C The work to be polished is mounted upon a series of carriages N which travel on tracks N longitudinally of the series of standards A and beneath the overhanging portions I and J. As shown, a radiator shell 0 is mounted on the carriage N so that the front face of the shell will come into operative relation to the grinder wheel K as the carriage N travels along the track N. Any suitable means may be used for propelling the carriage N along the tracks N and at the completion of the operation by successive grinders and polishers the Work will be removed from the carriages and the latter returned along tracks N in the space beneath the arched standards A.

To perform the grinding and polishing operation the frame C must be reciprocated so that the grinder wheel will traverse the face of the shell from bottom to top or in case the grinding and polishing is on the top of the shell the movement must extend from one side to the other. This movement is imparted to the frame C by the swinging of the frame B and this in turn is actuated by mechanism of the following construction:

P is an electric motor mounted on the shelf 1? secured to the standard A. P is a reduction worm gearing actuated by the motor shaft and driving a transverse shaft P at greatly reduced angular speed. Further speed reduction is effected through the sprocket and chain connection P between the shaft P and a parallel shaft P and through the chain P to a shaft P The latter shaft extends through a housing Q within which is arranged on the shaft P a sprocket wheel Q for driving a chain Q passing around an idler sprocket Q This chain has attached to one of the links thereof a pin Q which extends through a slot R in a rock arm R mounted on a rock shaft R The arrangement is such that the travelling of the link through its orbit will cause a reciprocation or rocking movement of the arm R and through this a rocking of the shaft R The shaft R extends out from the casing Q and has mounted thereon a rock arm R which is connected by a link S with the frame 13 so that the rocking of the arm R will cause a rocking movement of the frame B. This in turn will reciprocate the frame C causing the grinder wheel to traverse the work which is to be polished. To permit of stopping the movement of the frames B and C while the rock shaft R continues to oscillate, I preferably provide a detachable connection between said shaft and the rock arm R This comprises a rock arm R which is fixed to the shaft R and is adjacent to the rock arm R which latter is pivoted upon the shaft B A coupling pin R normally connects the rock arms R and R so that they move together under the actuation of the shaft R This coupling pin is connected to a pivoted arm R which in' turn is connected through a flexible chain R with a rock arm R on a rock shaft R The shaft R extends forward on the horizontal beam J and has an actuating handle R normally held from movement by a locking mechanism R The arrangement is such that any time it is desired to stop the oscillation of the frames Band C the lever R is unlocked and rocked so as to cause the rock arm R to actuate the pivoted arm R and withdraw the coupling pin R As soon, however, as the lever R is restored to normal position, a spring R will return the locking pin R and cam faces R on the rock arm R will guide this pin into its locking socket.

By reason of the pivotal connection of the frame C to the frame B at D the grinder wheel is permitted to follow the contour of the work, without regard to the path of movement of the shaft D. However, as a considerable weight is carried on the frame 0 together with the frame B, it is desirable to avoid an unnecessary lifting of this weight during the reciprocating movement. This I have effected by the contour of the track I which is so fashioned that while the roller 1-} may be lifted or depressed during'the movement, the center of gravity of the entire structure does not vary in height greatly during the entire reciprocation. It is, however, desirable to have a slight lifting of the center of gravity at each end of the movement as this assists in overcoming the inertia of the moving mass during retardation of the same prior to reversal and also assists in accelerating the movement after reversal. In this way the work which is performed by the reciprocating mechanism is lessened, reducing strain upon and wear of the parts. During the intermediate portion of the reciprocation the center of gravity remains at substantially a constant level with no tendency to move the frames B and C in either direction.

To prevent the dropping down of the grinder wheel at the opposite ends of the reciprocating movement and also in the spaces between succeeding phases of work, a guide track J is formed on the member J and a roller T engages this track. This roller is connected to the forward end of the frame C through the medium of a bracket T on said frame and a lever arm T pivoted to said bracket and carrying at its free end the roller '1. The lever T is normally free to rock on its pivotal connection to the bracket T during the reciprocation of the frames B and C so that the roller can traverse the straight track without interference with the lifting or dropping of the grinder wheel. The lever T is, however, limited in its rocking movement by a link 'I engaging a bearing on the bracket arm T and this may be set so that the grinder can not drop below a certain predetermined limit and this limit is below the lowest portion of the surface to be ground but above the supporting carriage for the work. This same lever T may be used for lifting the grinder wheels so as to clear the work whenever it is desired to exchange one grinder wheel for another.

With an apparatus as described, in operation the work such as radiator shells, is mounted upon successive carriages N and then fed forward on the track N to pass the successive grinder wheels of the series. The forward movement-is sufficiently slow so that the grinder or polishing wheel will complete its reciprocation before the work has advanced on the carriage a greater distance than the width of the wheel. In this way successive wheels which carry abrasive of different degrees of fineness will first rough grind the surface and then fine grind and finally polish before the entire series has been passed. I also find it advantageous to arrange alternate grinding wheels with their planes of rotation in angular relation to each other as illustrated in Figure 3. This change of direction will eliminate scratches in the surface being ground and produce a better polish.

The carriages N may be advanced along the tracks by any suitable mechanism such as the sprocket chain N driven by the shaft N and suitable connecting mechanism which will not be described in detail. The housing Q is preferably filled with lubricant so that the mechanism therein is maintained well lubricated at all times and is protected from the dust of grinding.

What I claim as my invention is:

1. A grinding machine comprising a vertical oscillatory frame, a horizontal frame pivotally connected to said oscillatory frame, a grinder wheel and an electric motor for actuating the same carried upon said horizontal frame, and so counter-balanced that the grinder wheel is pressed downward with a predetermined pressure, means for reciprocating said vertical frame and guide means for said frame adapted to main tain a substantially uniform height of the center of gravity during all but the end portions of the reciprocating orbit.

2. A grinding machine comprising a swinging support, a frame pivotally connected to and suspended from said swinging support, a grinder wheel and an electric motor for driving the same mounted on said pivotal frame, said frame being counter-balanced to limit the downward pressure of said grinder wheel to a predetermined amount, means for oscillating said swinging support, a roller bearing on said swinging support and a track over which said roller travels fashioned to maintain the center of gravity of the assembly at substantially constant height during the reciprocating movement with a slight rise at the opposite ends thereof.

3. A grinding machine comprising a supporting frame, a swinging member upon said frame, a link pivotally connected to said frame and t the upper end of said swinging member, a frame pivotally connected to and supported by the lower end of said swinging member, a grinder Wheel and an electric motor for driving the same mounted on said pivotal frame and counter-balanced to limit the downward pressure of the grinder, mechanism including a reciprocating connecting 

